_THE CROTALIDÆ._
IN the several chapters in which the rattlesnake has been introduced,
the reader has seen that for about 250 years it has been an object of
interest and of study among naturalists, and that first one and then
another has made fresh examinations of its various parts, giving to the
world new items of information as the results of such observations.
And can there remain anything further to find out about it? we may
ask in surprise. Yes, there is. There yet remains to comprehend and
decide upon one feature which thus far has defeated conjecture and
investigation—the ‘pit’ (p. 277). Possibly among the indefatigable
observers in the land of rattlesnakes, recent labours may have been
rewarded by some new evidence of the utility of this peculiar orifice,
and already their zoological journals may have enlightened ophiologists
on its functions. At the present moment I am not aware of such
information; and time will not permit of further delay to enable me to
send a message of inquiry across the great deep.
Hitherto the pit has certainly plagued not only zoologists, but all
classifiers of the Ophidia; because serpents that have this facial
depression embrace so many widely differing genera, some of them
resembling in all other respects the true vipers, and others the
rattlesnakes, so that they have come to be distinguished as the ‘pit
vipers.’
One of our most able biologists, A. R. Wallace, in his _Geographical
Distribution of Animals_,[106] informs us that ‘the _Crotalidæ_,
including the deadly rattlesnakes, abound most in the oriental regions’
(though not a single rattlesnake is found there, or in the Old World at
all). Let us seek for the reason of this apparent incongruity, and how
it is that a large number of serpents which have no rattle come to be
placed among those which have an instrument specially constructed to
produce a rattling sound.
Not to weary the reader by attempting to describe the various systems
of classification adopted by the many herpetologists who were the
contemporaries and immediate successors of Linnæus, we will rather
invite his imagination to picture the geographical history of our
globe during that age. Travels, explorations, the establishment of
new colonies, and the settlement of new territories marked the era;
and, as a sequence, new and hitherto unknown fauna were continually
brought home to Europe. We have seen, too, how natural history had been
growing into a science, and how travellers and zoologists stimulated
each other by their researches and writings. To recall a few of the
names with whom reptiles are associated, and to remind the reader that
one arranged them according to their scales, another their form, a
fourth their teeth, a fifth their habits, and so on, and that even
at the present day the classification of them is far from complete,
the present writer will be absolved from attempting anything beyond
generalization.
Studying snakes towards the end of the last century, were Laurenti,
Buffon, Bonnat, Lacepède, Klein, Seba, etc.
In the early part of the present century were Latreille, Shaw,
Daudin, Oppel, Merrem, Wagler, Neuwied, Cuvier, and many others till
we come to Gray, Fitzinger, and Dumeril, 1844. This last author, in
his introduction to _Les serpents solenoglyphes, dit Thanatophides_,
including the most deadly snakes, devotes several pages to the subject
of the ‘pit,’ and why it had especially occupied the attention of
those herpetologists who were endeavouring to improve the previously
imperfect systems. Wagler in 1824 assigned the name _Bothrops_ (from
βὀθρος, any hole, or pit, or hollow dug) to vipers with the pit that
had only scales and no plates or shields on their head, separating
these from the rattlesnakes and from those that have shields (see
illus. p. 318). This nomenclature of Wagler’s did not commend itself to
other herpetologists, and Fitzinger, in his _Systema Reptilium_, 1843,
extending the group, retained the name for one of the five families
into which he divided all the venomous snakes. Fitzinger’s fifth
family, the _Bothrophides_, included some of the Indian pit vipers; but
as some of these latter have shields on their head, they could not be
admitted into Wagler’s group with scales only. As the present object is
to demonstrate some of the perplexities of naturalists, and to arrive
at the reason why so many snakes without the _crotalon_ are called
_Crotalidæ_, we will quote Dumeril’s reasons, inviting the reader to
picture to himself the interest with which new examples were brought
home for investigation, and the obstacles presenting themselves to
herpetologists, who find one feature claiming alliance to this snake,
while another feature points an alliance to an entirely opposite one.
So Dumeril shows us why some of the herpetologists wished to admit
_every species that has the nasal fosse_ under the generic name
_Bothrophidæ_, and others would have limited the term to a few, because
the name does not suit them all equally well. ‘_Beaucoup d’autres
serpents presentent aussi des enfoncements creusés sur la tête et sur
le bord des lèvres._’ These depressions, called by Professor Owen
‘secreting follicles,’ may be easily distinguished on the upper lip
of some of the larger constrictors. In the Reticulated python you can
count these pits like deep dimples round the mouth. In the Diamond
snake (_Morelia spilotes_) they are remarkably deep along the lower lip.
Of those ‘follicles’ in the _Crotalidæ_ Dumeril writes: ‘_Les fossettes
paraissent devoir être des organes particuliers dont l’usage ou la
fonction n’est pas connu il est vraix, mais qui semble avoir quelque
importance par leur position constante entre les orifices réels des
narines et les yeux, at leur structure anatomique assez compliquée.
À cause de la grande analogie qu’ils ont tous avec les serpents à
sonnettes, nous avons preféré appeler ceux-ci les crotaliens._’[107]
The above words are under the head of ‘_Les Crotaliens_,’ a name
retained, he had already explained why. ‘_Les solenoglyphes qui ont les
narines doubles en apparence seront pour nous les Crotaliens quoique
cette dénomination puisse, à tort, porter à croire que ces espèces
font du bruit avec leur queue: elle indique seulement leur rapports
avec les crotales établis d’après la présence des fausses narines
ou fossettes dont nous venons de parler. On nomme quelquefois ces
Ophidiens Bothrops._’[108] ... ‘_Comme ce caractère conviendrait à tous
les Crotaliens parcequ’ils ont tous des fossettes dites lacrymales, ce
nom (Bothrops) deviant par conséquent trop général._’[109]
In retaining _Bothrops_ as a generic distinction, a large number of
non-venomous and constricting serpents must have been included, which
probably induced Wagler’s opposers to say of him that he ‘created a
system in which the venomous and non-venomous were huddled together
pell mell.’
Thus we see that on account of the nasal fosse the Indian crotaline
snakes could not be true vipers; they could not be exclusively
_Bothrophidæ_, for the reasons given above, and they certainly are not
rattlesnakes; but for want of a better name they are ‘_Crotalidæ_,’ as
they have (minus the rattle) more features in common with rattlesnakes
than with any others.
In the slough of a rattlesnake you may see the form of this pit. It is
lined with scales, and reversed in sloughing, perfectly shaped as a
tiny glove finger.
When Dr. J. E. Gray, F.R.S., etc., edited a short-lived little magazine
in 1831 called the _Zoological Miscellany_, the whole of the known
_Crotalidæ_ consisted of ten genera and thirty species, of which
sixteen species belonged to Asia and its adjacent islands, one to South
Africa, and the rest to America. When he published his catalogue of
snakes belonging to the British Museum in 1849, he enumerated eleven
genera and thirty-seven species. Wallace, 1876, gives eleven genera and
forty species, the eastern examples of which belong to India, Siam,
Java, Borneo, Tartary, Thibet, Japan, and Formosa. Still more recently
some belonging to the Western States of America have, I believe, been
added by Cope or Coues, the latter informing us that up to the date of
his paper, 1878, eighteen species and upwards of the rattlesnake proper
had been described in the United States, nearly all in the west and
south-west. So, as those vast deserts are being explored, new species
are continually discovered.
Of the Indian species of _Crotalidæ_, those minus a rattle, Fayrer
says that they are chiefly in Malaya and Indo-China. Many of them,
the _Trimeresuri_, are arboreal, and like the foliage in colour. They
have the viperine aspect, but are ‘less formidable than their American
congeners,’ being of much smaller dimensions. Only one, _Halys_, has
anything approaching to a rudimentary rattle, a tail ending in a spine.
Of the _Trimeresuri_, the tree species, Fayrer affirms that few deaths
are ascribed to them. Some attain to above three feet in length. He
thinks a feeble person might die of their bite. They are of a sluggish
habit, and lie quietly hidden among the leaves of low bushes and ferns.
They will even suffer themselves to be moved without attempting to
bite, but one that was pressed to the ground with a stick struck so
hard as to break both its fangs. They feed chiefly on insects. Their
habits are crepuscular if not nocturnal, and Fayrer does not state
positively that they or any of the Indian _Crotalidæ_ are viviparous.
Of the principal American _Crotalidæ_ that are not true rattlesnakes,
the ‘Bushmaster’ (_Lachesis mutus_) stands first. This is undoubtedly
the largest venomous serpent known. In length it equals the Hamadryad;
and in thickness, the large African vipers. On looking closely at the
illustration of this reptile’s tail (p. 176), it will be seen that
in addition to the spine which terminates it, there are several rows
of fine, elaborated scales, which under the microscope appear almost
as curiously pointed as those on the head of _Vipera nasicornis_.
Dumeril thus describes the tail: ‘_Ponctuée, et précédée de dix ou
douze rangées d’écailles épineuses, un peu courbées en crochets à
la pointe._’ This is the snake called _Crotalus muet_, or ‘dumb
rattlesnake,’ by Linnæus, and which is supposed to simulate the sound
of the rattle by vibrating this point against the leaves; but many
other snakes do this whether their tail is pointed or not, as we saw
in chap. xi. Any small thing, such as a twig rustling among dead
leaves, would produce the same sound. The near approach of _Lachesis_
to _Crotalus horridus_ of the same habitat is, however, seen in this
rudimentary rattle, the agitation of which may similarly be attributed
to the timidity of these ‘highly nervous and irritable creatures,’ to
repeat Coues’ words; for deadly as they are, timidity strongly displays
itself. Watching the venomous snakes when their food is dropped into
their cages, their excessive caution, amounting to cowardice, is
remarkable, and this with the rattlesnakes especially. One will fix
its eyes on the rat which is running about, and shrink back terrified
if it approach too closely. Then if the quadruped is a moment quiet,
the snake appears to be considering whether it will be advisable to
attack it or not. Stealthily and slowly it approaches its head, but on
the slightest movement of the little animal, recedes in alarm, and is
some time before it makes a second venture. I have seen a rattlesnake
thus timidly advancing and recoiling three or four times before it
has the courage to give the fatal stroke. Even after the bite it
watches its victim with a steadiness in which terror is the strongest
expression; and when the rat has remained motionless for a time, and
the rattlesnake ventures near to investigate and make sure it is
dead, one faint gasp or dying struggle will cause the reptile to dart
back in excessive alarm, and wait again some minutes before venturing
near. After long and patient observations, I am still doubtful whether
stupidity or timidity predominates in viperine natures.
Of the other well-known and formidable American _Crotalidæ_ is the
‘_Fer de lance_’ (_Trigonocephalus lanceolatus_) of the Antilles
and Central America. This has also a pointed tail. The Jararaca of
Gray (_Craspedocephalus Braziliensis_) is another, but without the
point. Of the true rattlesnakes, Dumeril gave five genera in 1844,
viz. _Crotalophorus_, _Crotalus_, _Caudisona_, _Urocrotalon_, and
_Urosophus_.
From the two species originally known, we see how they have gradually
multiplied as the country has been more thoroughly explored. In 1860,
Dr. Weir Mitchel affirmed that twenty species had been then described;
probably the most recent ‘Reports’ or Bulletins will tell us of yet
others. And these latter are exclusive of the non-rattle-bearing
_Crotalidæ_.
Dr. Mitchel’s experiments were with the northern species, chiefly
_Cro. durissus_; and as a relief from this wearisome classification,
some of his observations will be welcome. One very noteworthy result
is that the Crotalus does occasionally produce a sound independently
of the rattle. Not a prolonged hiss, or by any means so loud as the
innocent snakes, but merely ‘the expiration of air from the lungs just
before striking.’ I have never observed or heard this in our London
rattlesnakes, but it no doubt is of the same character and degree of
sound as that produced by the _Cerastes_ and the little _Echis_, and
which more resembled a short, feeble, spitting sound. Still, as we are
informed by Dumeril that rattlesnakes are ‘deprived of voice,’ it is
interesting to know that, on the authority of Dr. Weir Mitchel, some
slight sound, though not a regular hiss, does sometimes accompany the
action of striking.
An inquiry has lately met the eye in one of our scientific journals
as to whether a rattlesnake drinks. Dr. Mitchel clears away all
doubts on that subject by impressing upon those who keep these
creatures the importance of giving them plenty of water, particularly
when changing the skin. Deprived of it, the cuticle comes off
unhealthily—_desquamates_, in fact, in bits. At the casting of the
cuticle, or previous to the process, they will not only drink, he tells
us, but lie for hours in the water. When they were disinclined to eat,
and had fasted long enough to endanger their health, he fed them by
force with milk and insects, and the way he managed was to get their
mouths open and insert a tunnel a safe distance down their throat.
While held in this position, a repast consisting of insects and milk
was pushed down the tube of the tunnel in sufficient quantities. The
most surprising circumstance in connection with this style of feeding,
and also with the process adopted by Dr. Shortt of Madras in filling
his cobras ‘as full as they could hold’ with sour milk, is that these
fastidious and frightened reptiles did not disgorge the diet. Both
experimentalists, however, found it answer, reminding us of some
advice given to the keeper at the London Ophidarium in the case of the
Hamadryad, which, having no snakes to dine off one winter, elected to
fast. To force frogs or fish down its throat was suggested; but no one
could be found brave enough to undertake the task, and happily ‘Ophio’
survived till a relay of ring snakes arrived.
Both Mitchel and Coues corroborate what has been observed by others
regarding the increased virulence of the bite when moulting; but both
are of opinion that this is owing to an accumulation of venom, as the
snakes have not been feeding or expending their store for some days.
Even while not feeding, their venom is secreted all the same, and they
survive many months, even a whole year and more, without food. Dumeril
mentions one that lived twenty-five months without feeding.
A startling and almost horrifying demonstration of what physiologists
would perhaps attribute to nervous or to muscular irritability is
described by Dr. Mitchel, namely, an action that had been begun in
life, carried out in a headless snake. On p. 281 was described the
astonishment of Colonel Beverley, who observed the severed head of a
rattlesnake attempting to bite. ‘Then the head gave a sudden champ.’
Long after a snake is dead the tongue will be exserted as in life;
and in other actions they, as it were, carry out their intentions
though deprived of vitality. ‘The headless trunk will strike,’ says Dr.
Mitchel, and continue to do this when touched or irritated as if it
still had its head and its fangs to strike with!
Mr. George Catlin in his _Life among the Indians_ relates a
circumstance of this kind which may well be introduced here, as
illustrative of this amazing fact—a rattlesnake coiling and springing
after it is decapitated. His party were going down a river, and had
just landed to explore a little, when he saw a large Crotalus, and
seizing his gun fired at its head. At the same moment it leaped and
sprang towards him, apparently striking him on the breast, Mr. Catlin
being on the point of leaping back into the boat. He thought he had
fired and missed his aim, and was a dead man, nevertheless much
wondering at having missed his mark. Meantime, an Indian, seeing a spot
of blood on the front of Mr. Catlin’s linen smock, exclaimed, ‘You are
bitten!’ and without ceremony the smock and flannel shirt were torn
open, and a spot of blood on his breast was exposed to view. Promptly
the blood was washed off, and the Indian on his knees had his mouth
at the wound preparing to suck out the poison. Quickly looking up,
however, he rose to his feet, and with a smile of exultation said,
‘There’s no harm! You’ll find the snake without its head.’
Stepping ashore again, and pushing aside the long grass, there, sure
enough, was the headless rattlesnake, coiled up where it had fallen,
and with its headless trunk erect, ready for another spring. Mr. Catlin
had _not_ missed fire, but the creature so near the spring, was so
ready at the instant with its aim made, that it leapt and struck Mr.
Catlin probably on the very spot where it would have bitten him had the
sportsman missed his mark. The bleeding trunk had printed its stroke
with blood, driving the stain through the dress to the skin. ‘How
curious it is,’ Mr. Catlin remarks at the conclusion of his narrative,
‘that if you cut off the head of a rattlesnake, its body will live
for hours, and jump at you if you touch it with a stick, when if you
break his spine near the tail, with even a feeble blow, it is dead in a
minute. This we proved on several occasions.’
Mr. Catlin also helps to confirm what has been already stated in these
pages, viz. the certainty of the mate being within hearing of the
rattle, and responding when one of them sounds an alarm; also that
‘they can track each other and never lose company, though when met are
not always seen together, so that if we kill one over-night and leave
its dead body, the other will be found by its side in the morning.’
A near relative of the rattlesnake is the ‘copper-head,’
_Trigonocephalus contortrix_ of the United States, known also as the
‘Red adder,’ and the ‘Dumb rattlesnake.’ It is the _Boa contortrix_ of
Linnæus, who, as we explained above, and also in chap. ii., divided the
Ophidia into only three or four families, calling an immense number,
both venomous and harmless, ‘boas.’
This member of the _Crotalidæ_ is said to be as venomous as the
rattlesnake, and is much more dreaded, because it has no rattle to give
warning of its proximity. When a bitten person survives, the effects
of its bite are said to be felt annually, as in the case of the
rattlesnake, and the injured limb ‘turns the colour of the snake.’ In
regard to this latter symptom, said to show itself in the case of so
many snakes, the bitten limb assumes all manner of horrible tints in
most cases, and it does not require a great stretch of imagination to
detect colours resembling the also many-tinted aggressors. Still there
may be more in this than we at present know of.
In the cranberry swamps and tamarack marshes in the northern districts
of Ohio formerly were found immense numbers of a small and very
dark brown rattlesnake known as the _Massasauga_. It is seen lying
in clusters like small twigs on dry leaves, and still is found in
considerable numbers in some remote districts. The illustration of the
small rattle (p. 302) was sent me from that neighbourhood, and is, I
believe, from a true ‘Massasauga.’ This is the one (as I think I am
safe in stating) that was first (1810) described by Dr. Kirtland, a
distinguished naturalist of Ohio, and after him named _Crotalophorus
Kirtlandi_. Its range is confined to the swampy districts of Northern
Ohio and Southern Michigan. Its rattle being scarcely audible,
this little snake gets frequently trodden upon, and persons are as
frequently bitten; but Dr. Kirtland stated that he had never known any
one to die of its bite, which is scarcely worse than the sting of a
hornet. It is a link between the last-named snake, the ‘copper-head,’
and the rattlesnake, having head-shields like the former, and tail of
the latter. These small species no doubt help to add to the confusion
of evidence regarding the virulence of rattlesnake bites, one person
affirming that they are deadly, and another, that recovery is common.
The degree of venom between the smallest and the largest of the
_Crotalidæ_ can no more be compared than can the constriction of
the little slow-worm round your fingers with the constriction of the
anaconda.
A word in conclusion about the rattlesnake’s enemies; and of these hogs
come first, next to man. Wild hogs, peccaries, and deer in their native
haunts, and doubtless an immense number of snake-eating birds, devour
young rattlesnakes. Deer strike them with their hoofs, jumping on them
with wonderful adroitness, so as to pin them down with all four feet.
Pigs in the west derive no small part of their subsistence from snakes;
and, as is now a well-known fact, the introduction of hogs has done
more than anything else—not even excepting the annual _battue_—to
diminish the number of rattlesnakes. The venom being ‘innocuous to
hogs,’ is a fact only partially stated. A thin hog, bitten on a vein,
might die as speedily as any other victim. It is because the venom
fails to penetrate the fat, or, as Dr. Coues more ably expresses it,
‘the fluid fails to enter the circulation through the layer of adipose
tissue.’ Pigs are not invariably exempt, any more than is the mongoose,
from the cobra’s bite. In both cases adroitness assists the animals to
evade the strike, and in the latter case the thick fur of the mongoose
is as great a protection to it as the fat is to the hog.
Dr. Coues mentions a danger not often anticipated in dealing with
rattlesnakes when you wish to examine them. This is their habit of
twining themselves around the arm, or wherever they can get hold.
‘Grasp it fearlessly at the back of the neck,’ he says; ‘but even then
a large one can constrict enough to paralyze both arms.’ A man who was
thus trammelled had to be relieved by a bystander. We are not always
prepared for constricting rattlesnakes!
[Illustration]